Human rights activists in Chile have expressed shock and concern after masked attackers stabbed three women at a protest in favour of free and legal abortion.

One of the women was wounded in the stomach and two others in the legs during a march in the country’s capital, Santiago, on Wednesday. Their injuries were not described as life-threatening. A policeman was also hurt in the incident.

No suspects have been arrested, but participants in the march argue that anti-abortion radicals are responsible.

“The protest began festive, but we felt the mood turn when we heard that a group of extremists had put up barricades and scattered animal guts on the ground,” said Antonia Orellana, a member of the Chilean Network Against Violence Toward Women and the leftwing Frente Amplio party.

One of the stabbing victims, a 24-year-old law student, released a statement in response to these accusations, testifying that her fellow protesters had not initiated violence. “It was an act of terrorism from a minority group that wants to scare us,” wrote the woman, who asked not to be named.

Abortion is criminalized or restricted in every Latin American country except for Cuba and Uruguay, but a movement to reform the region’s draconian laws has gained pace in recent months.

Chile had one of the strictest abortion policies in the world until the government of Michelle Bachelet eased a total ban to permit termination in instances of rape, if there is a risk to the mother’s life or if the foetus is not expected to survive.

Women’s rights supporters are concerned the government will backtrack on the progress seen under Bachelet, fearing the influence of extremely conservative politicians such as José Antonio Kast, who seeks to reinstate a total abortion ban with his newly formed movement, Republican Action.

On Thursday, Bachelet condemned the attacks, saying: “This kind of threat against social movements recalls the worst years of the dictatorship, and are unacceptable in a democratic country.”

Clashes are common between protesters and police in Chile, but such attacks on activists are not. Photograph: Ivan Alvarado/Reuters

But campaigners said the government’s response was muted, while the country’s largely rightwing media initially failed to cover the violence.

“No one paid attention,” said the comedian and radio presenter Natalia Valdebenito, who broke the news of the attack with a live Instagram post.

“The next morning, there was nothing on the newspaper covers, nothing on the television. I didn’t see the president condemning the attacks, nor did I see the minister of internal affairs,” she said.

While clashes are common between protesters and police in Chile, this type of attack on activists is not.

“We know there are organized groups that intentionally went to disrupt the protest and do harm,” said Valdebenito, “But the feminist movement will continue. We are united and they cannot imagine that type of strength.”